ESTEBAN E. SARMIENTO, JOHN F. OATES
American Museum Novitates 2000 (3304), 1-55, (16 October 2000) https://doi.org/10.1206/0003-0082(2000)3304<0001:TCRGAD>2.0.CO;2
This study presents the results of a new set of measurements made on museum specimens of gorilla skeletons from the Cross River headwaters. It provides a review of the taxonomy of Cross River gorillas and describes their distribution and related aspects of their natural history. Considering their distinctiveness and geographic isolation, Cross River gorillas are best regarded as a distinct subspecies, G. g. diehli. Compared to other western gorilla populations, Cross River gorillas have smaller dentitions, smaller palates, smaller cranial vaults, and shorter skulls. Although Cross River gorillas do not seem to differ from other western gorillas in either body size or limb long bone lengths, measurements from a single male suggest that they may have shorter hands and feet and a larger opposability index than other western gorillas. Marked variation in the habitats of Cross River gorillas and insufficient data on behavior frustrate attempts to directly associate morphology with ecology. Many of their distinguishing characters, however, are parts of an adaptive complex that in most primates is characteristic of increasing terrestriality. A subspecific designation for Cross River gorillas correlates with other biogeographic patterns, since many primate species and subspecies inhabiting the Cross River area are distinct from their counterparts further south where other western gorillas occur.